This invention relates generally to scuba diving equipment or apparatus and more particularly to pressure regulators/compressed breathing air tanks used in conjunction with training individuals in the use of underwater breathing apparatus.
Within the past several decades, the sport of skin-diving has enjoyed considerable popularity, so that today there exists an entire industry for supplying equipment for this sport. This industry manufactures and sells a wide variety of instruments, devices and equipment to enable a person to properly breathe underwater so as to enable him to remain beneath the surface for extended periods of time.
It is of course necessary for users of such underwater breathing apparatus to undergo a certain degree of training. In this regard, it is conventional to provide a compressed breathing air tank which supplies breathing air to a pressure regulator, the latter in turn supplying breathing air at a constant pressure level to a user of the equipment. It is known to incorporate therewith warning devices which sense the pressure in the air tank or at the input side of the pressure regulator so as to generate a signal (visual or audible, for example) when the pressure level in the air tank reaches a predetermined minimum level -- for the purpose of affirmatively informing the user of the equipment that his air supply is about to be depleted.
In training a user of underwater breathing equipment, it is of course important tht such user experience the warning signals as referred to hereinabove prior to completion of his training period. The difficulty encountered in this regard resides in the fact that standard air tanks used in scuba diving equipment are of such a size and pressurized to such a degree as to confine enough air to sustain a user for a substantial duration of time -- and during training exercises it is not convenient to wait until a standard air tank becomes sufficiently depleted to generate a warning signal.